Microstructure Evolution and Modeling of 2024 Aluminum Alloy Sheets During Hot Deformation Under Different Stress States

Lei Deng,Peng Zhou,Xinyun Wang,Junsong Jin,Ting Zhao 대한금속·재료학회 2018 METALS AND MATERIALS International Vol.24 No.1

In this work, specimens of the 2024 aluminum alloy sheet were compressed and stretched along the original rollingdirection at elevated temperatures. The microstructure evolution was investigated by characterizing the metallographicstructures via electron backscattered diffraction technology before and after deformation. It was foundthat while recrystallization occurred in the compressed specimens, it was not observed to the same extent in thestretched specimens. This difference in the grain morphology has been attributed to the different movement behaviorsof the grain boundaries, i.e., their significant migration in the compression deformation and the transformationfrom low-angle to high-angle boundaries observed mainly during tension deformation. The empirical model,which can describe the grain size evolution during compression, is not suitable in the case of tension, and therefore,a new model which ignores the detailed recrystallization process has been proposed. This model provides adescription of the grain size change during hot deformation and can be used to predict the grain size in the plasticdeformation process.

Prognostic Role of MicroRNA-21 in Non-small Cell Lung Cancer: a Meta-analysis

Ma, Xue-Lei,Liu, Lei,Liu, Xiao-Xiao,Li, Yun,Deng, Lei,Xiao, Zhi-Lan,Liu, Yan-Tong,Shi, Hua-Shan,Wei, Yu-Quan Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.5

Introduction: Many studies have reported that microRNA-21 (miR-21) mihght predict the survival outcome in non-small cell lung cancers (NSCLCs) but the opposite opinion has also been expressed. The aim of this study was to summarize the evidence for a prognostic role of miR-21. Materials and Methods: All the eligible studies was searched by Medline and EMBASE and patients' clinical characteristics and survival outcome were extracted. Then a meta-analysis was performed to clarify the prognostic role of the miR-21 expression in different subgroups. Results: A total of 8 eligible articles were yielded covering survival outcomes or clinical characteristics. The combined hazard ratio (HR) and 95% confidence interval (95% CI) for overall survival (OS) was 2.19 [0.76, 6.30], while the combined HR (95% CI) of Asian group for OS had a significant result, 5.49 [2.46, 12.27]. The combined HR (95% CI) for recurrence free survival or disease free survival (RFS/DFS) was 2.31 [1.52, 3.49]. Odds ratios (ORs) showed that the miR-21 expression was associated with lymph node status and histological type. Conclusion: miR-21 expression could predict the prognostic outcome of NSCLC in Asians, despite some deficiencies in the study data.

Simulation analysis and evaluation of decontamination effect of different abrasive jet process parameters on radioactively contaminated metal

Zhong Lin,Deng Jian,Zuo Zhe-wen,Huang Can-yu,Chen Bo,Lei Lin,Lei Ze-yong,Lei Jie-heng,Zhao Mu,Hua Yun-fei 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.11

A new method of numerical simulating prediction and decontamination effect evaluation for abrasive jet decontamination to radioactively contaminated metal is proposed. Based on the Computational Fluid Dynamics and Discrete Element Model (CFD-DEM) coupled simulation model, the motion patterns and distribution of abrasives can be predicted, and the decontamination effect can be evaluated by image processing and recognition technology. The impact of three key parameters (impact distance, inlet pressure, abrasive mass flow rate) on the decontamination effect is revealed. Moreover, here are experiments of reliability verification to decontamination effect and numerical simulation methods that has been conducted. The results show that: 60Co and other homogeneous solid solution radioactive pollutants can be removed by abrasive jet, and the average removal rate of Co exceeds 80%. It is reliable for the proposed numerical simulation and evaluation method because of the well goodness of fit between predicted value and actual values: The predicted values and actual values of the abrasive distribution diameter are Ф57 and Ф55; the total coverage rate is 26.42% and 23.50%; the average impact velocity is 81.73 m/s and 78.00 m/s. Further analysis shows that the impact distance has a significant impact on the distribution of abrasive particles on the target surface, the coverage rate of the core area increases at first, and then decreases with the increase of the impact distance of the nozzle, which reach a maximum of 14.44% at 300 mm. It is recommended to set the impact distance around 300 mm, because at this time the core area coverage of the abrasive is the largest and the impact velocity is stable at the highest speed of 81.94 m/s. The impact of the nozzle inlet pressure on the decontamination effect mainly affects the impact kinetic energy of the abrasive and has little impact on the distribution. The greater the inlet pressure, the greater the impact kinetic energy, and the stronger the decontamination ability of the abrasive. But in return, the energy consumption is higher, too. For the decontamination of radioactively contaminated metals, it is recommended to set the inlet pressure of the nozzle at around 0.6 MPa. Because most of the Co elements can be removed under this pressure. Increasing the mass and flow of abrasives appropriately can enhance the decontamination effectiveness. The total mass of abrasives per unit decontamination area is suggested to be 50 g because the core area coverage rate of the abrasive is relatively large under this condition; and the nozzle wear extent is acceptable

Genome-wide Association Studies for Osteoporosis: A 2013 Update

Hong-Wen Deng,Lei Zhang,Christopher J. Papasian,Hong-Wen Deng 대한골대사학회 2014 대한골대사학회지 Vol.21 No.2

In the past few years, the bone field has witnessed great advances in genome-wide as-sociation studies (GWASs) of osteoporosis, with a number of promising genes identified. In particular, meta-analysis of GWASs, aimed at increasing the power of studies by com-bining the results from different study populations, have led to the identification of nov-el associations that would not otherwise have been identified in individual GWASs. Re-cently, the first whole genome sequencing study for osteoporosis and fractures waspublished, reporting a novel rare nonsense mutation. This review summarizes the im-portant and representative findings published by December 2013. Comments are madeon the notable findings and representative studies for their potential influence and im-plications on our present understanding of the genetics of osteoporosis. Potential limi-tations of GWASs and their meta-analyses are evaluated, with an emphasis on under-standing the reasons for inconsistent results between different studies and clarificationof misinterpretation of GWAS meta-analysis results. Implications and challenges ofGWAS are also discussed, including the need for multi- and inter-disciplinary studies.

Differences in the mandibular premolar positions in Angle Class I subjects with different vertical facial types

Jun Duan,Feng Deng,Wan-Shan Li,Xue-Lei Li,Lei-Lei Zheng,Gui-Yuan Li,Yan-Jie Bai 대한치과교정학회 2015 대한치과교정학회지 Vol.45 No.4

Objective: To compare the positions of the mandibular premolars in Angle Class I subjects according to vertical facial type. The results will provide a theoretical basis for predicting effective tooth movement in orthodontic treatment. Methods: Cephalometric parameters were determined using cone-beam computed tomography in 120 Angle Class I subjects. Subjects were categorized as short, normal, and long face types according to the Frankfort mandibular angle. Parameters indicating the position of the mandibular right premolars and the mandible were also measured. Results: The angle between the mandibular first premolar axis and buccal cortex, the distance between the root apex and buccal cortex, angle of vestibularization, arc of vestibularization, and root apex maximum movable distance were significantly greater in the short face type than in the long and norm face types. The angle between the mandibular second premolar axis and buccal cortex, the distance from root apex to buccal cortex, and the arc of vestibularization were significantly greater in the short face type than in the normal face type. Conclusions: There are significant differences in the mandibular premolar positions in Class I subjects according to vertical facial type.

A Novel Kinetic Analysis of Crystallization of Polypropylene (PP) in Dynamically-vulcanized PP/Ethylene-propylene-diene Rubber (EPDM) Blends Using an In-situ Measurement Technique

Lei Hu,Bin Yang,Yan-Li Deng,Fei-Xue Lu,Ru Xia,Zheng-Zhi Zheng,Ji-Bin Miao,Jia-Sheng Qian,Chuan-Ru Zhang,Peng Chen,Yu-Chuan Zhang 한국고분자학회 2017 폴리머 Vol.41 No.4

The effects of cooling medium temperatures and plastic/rubber ratios on solidification and crystallization kinetics of dynamically-vulcanized polypropylene/ethylene-propylene-diene rubber (PP/EPDM) blends were investigated with the aid of an in-situ measurement technique. The cooling medium temperature heavily influenced the solidification kinetics primarily due to a combination of latent heat liberated from the molten polymer and the heat transferred away via the metallic wall during the cooling period. Interestingly, the parameter C in three-parameter model was not only affected by the material properties, but also by the cooling condition, different from the previous literature. The crystallization kinetics analysis indicated that the effect of EPDM in the blends consisted of both nucleation-promoting effect (low EPDM loading) and steric effect (higher EPDM loading). The present kinetic analysis may be helpful to further studies on improving the product performances for industrial applications.

A comprehensive survey of genomic alterations in gastric cancer reveals systematic patterns of molecular exclusivity and co-occurrence among distinct therapeutic targets

Deng, Niantao,Goh, Liang Kee,Wang, Hannah,Das, Kakoli,Tao, Jiong,Tan, Iain Beehuat,Zhang, Shenli,Lee, Minghui,Wu, Jeanie,Lim, Kiat Hon,Lei, Zhengdeng,Goh, Glenn,Lim, Qing-Yan,Tan, Angie Lay-Keng,Sin P BMJ Group 2012 Gut Vol.61 No.5

<P><B>Objective</B></P><P>Gastric cancer is a major gastrointestinal malignancy for which targeted therapies are emerging as treatment options. This study sought to identify the most prevalent molecular targets in gastric cancer and to elucidate systematic patterns of exclusivity and co-occurrence among these targets, through comprehensive genomic analysis of a large panel of gastric cancers.</P><P><B>Design</B></P><P>Using high-resolution single nucleotide polymorphism arrays, copy number alterations were profiled in a panel of 233 gastric cancers (193 primary tumours, 40 cell lines) and 98 primary matched gastric non-malignant samples. For selected alterations, their impact on gene expression and clinical outcome were evaluated.</P><P><B>Results</B></P><P>22 recurrent focal alterations (13 amplifications and nine deletions) were identified. These included both known targets (<I>FGFR2</I>, <I>ERBB2</I>) and also novel genes in gastric cancer (<I>KLF5</I>, <I>GATA6</I>). Receptor tyrosine kinase (RTK)/RAS alterations were found to be frequent in gastric cancer. This study also demonstrates, for the first time, that these alterations occur in a mutually exclusive fashion, with <I>KRAS</I> gene amplifications highlighting a clinically relevant but previously underappreciated gastric cancer subgroup. <I>FGFR2</I>-amplified gastric cancers were also shown to be sensitive to dovitinib, an orally bioavailable FGFR/VEGFR targeting agent, potentially representing a subtype-specific therapy for <I>FGFR2</I>-amplified gastric cancers.</P><P><B>Conclusion</B></P><P>The study demonstrates the existence of five distinct gastric cancer patient subgroups, defined by the signature genomic alterations <I>FGFR2</I> (9% of tumours), <I>KRAS</I> (9%), <I>EGFR</I> (8%), <I>ERBB2</I> (7%) and <I>MET</I> (4%). Collectively, these subgroups suggest that at least 37% of gastric cancer patients may be potentially treatable by RTK/RAS directed therapies.</P>

Cholecystokinin facilitates glutamate release by increasing the number of readily releasable vesicles and releasing probability.

Deng, Pan-Yue,Xiao, Zhaoyang,Jha, Archana,Ramonet, David,Matsui, Toshimitsu,Leitges, Michael,Shin, Hee-Sup,Porter, James E,Geiger, Jonathan D,Lei, Saobo The Society 2010 The Journal of neuroscience Vol.30 No.15

<P>Cholecystokinin (CCK), a neuropeptide originally discovered in the gastrointestinal tract, is abundantly distributed in the mammalian brains including the hippocampus. Whereas CCK has been shown to increase glutamate concentration in the perfusate of hippocampal slices and in purified rat hippocampal synaptosomes, the cellular and molecular mechanisms whereby CCK modulates glutamatergic function remain unexplored. Here, we examined the effects of CCK on glutamatergic transmission in the hippocampus using whole-cell recordings from hippocampal slices. Application of CCK increased AMPA receptor-mediated EPSCs at perforant path-dentate gyrus granule cell, CA3-CA3 and Schaffer collateral-CA1 synapses without effects at mossy fiber-CA3 synapses. CCK-induced increases in AMPA EPSCs were mediated by CCK-2 receptors and were not modulated developmentally and transcriptionally. CCK reduced the coefficient of variation and paired-pulse ratio of AMPA EPSCs suggesting that CCK facilitates presynaptic glutamate release. CCK increased the release probability and the number of readily releasable vesicles with no effects on the rate of recovery from vesicle depletion. CCK-mediated increases in glutamate release required the functions of phospholipase C, intracellular Ca(2+) release and protein kinase Cgamma. CCK released endogenously from hippocampal interneurons facilitated glutamatergic transmission. Our results provide a cellular and molecular mechanism to explain the roles of CCK in the brain.</P>

Influences of Solution pH and Redox Potential on the Bioleaching of LiCoO2 from Spent Lithium-ion Batteries

Lei Li,Gui-sheng Zeng,Shenglian Luo,Xiao-rong Deng,Qing-ji Xie 한국응용생명화학회 2013 Applied Biological Chemistry (Appl Biol Chem) Vol.56 No.2

The influences of solution pH and redox potential on bioleaching of LiCoO2 from spent lithium-ion batteries using Acidithiobacillus ferrooxidans were investigated. Bioleaching at different initial pH and ferrous ion (Fe2+) concentrations were carried out, and electrochemical behavior of LiCoO2 dissolution was examined to study the effect of solution redox potential on the bioleaching process. The results showed maximum cobalt dissolution at initial pH of 1.5 and initial Fe2+ concentration of 35 g/L, and cobalt dissolution showed only slight relationship with pH of solution. Nonetheless, there was improvement of cobalt dissolution at higher redox potential. The cyclic voltammograms showed that dissolution rates increase when the solution potentials are higher than 0.4 V, and rapid decrease at 1.3 V. The anodic polarization curves indicated that the corrosion, primary passive, and passivation potentials were 0.420, 0.776 and 0.802 V, respectively.

Flexural behaviour of steel plate-masonry composite beams

Deng-Hu Jing,Shuang-Yin Cao,Lei Shi 국제구조공학회 2012 Steel and Composite Structures, An International J Vol.13 No.2

Steel plate-masonry composite structure is a newly-developed type of structural technique applicable to existing masonry buildings by which the load-bearing walls can be removed for large spaces. This kind of structure has been used in practice for its several advantages, but experimental investigation on its elements is nearly unavailable in existing literature. This paper presents an experimental study on the flexural behaviour of four steel plate-masonry composite beams loaded by four-point bending. Test results indicate that failure of the tested beams always starts from the local buckling of steel plate, and that the tested beams can satisfy the requirement of service limit state. In addition, the assumption of plane section is still remained for steel plate prior to local buckling or steel yielding. By comparative analyses, it was also verified that the working performance of the beam is influenced by the cross-section of steel plate, which can be efficiently enhanced by epoxy adhesive rather than cement mortar or nothing at all. Besides, it was also found that the contribution of the encased masonry to the flexural capacity of the composite beam cannot be ignored when the beam is injected with epoxy adhesive.